|
| 1 | +// https://leetcode.com/problems/find-the-distinct-difference-array |
| 2 | +// N: length of array |
| 3 | +// T: O(N) |
| 4 | +// S: O(N) |
| 5 | + |
| 6 | +import java.util.HashMap; |
| 7 | +import java.util.Map; |
| 8 | + |
| 9 | +public class FindTheDistinctDifferenceArray { |
| 10 | + public int[] distinctDifferenceArray(int[] nums) { |
| 11 | + final Map<Integer, Integer> leftFrequencies = new HashMap<>(); |
| 12 | + final Map<Integer, Integer> rightFrequencies = getNumberFrequencies(nums); |
| 13 | + final int[] result = new int[nums.length]; |
| 14 | + int k = 0; |
| 15 | + for (int element : nums) { |
| 16 | + addToFrequency(leftFrequencies, element); |
| 17 | + removeFromFrequency(rightFrequencies, element); |
| 18 | + result[k++] = leftFrequencies.size() - rightFrequencies.size(); |
| 19 | + } |
| 20 | + return result; |
| 21 | + } |
| 22 | + |
| 23 | + private void removeFromFrequency(Map<Integer, Integer> frequencies, int element) { |
| 24 | + if (frequencies.get(element) == 1) { |
| 25 | + frequencies.remove(element); |
| 26 | + } else { |
| 27 | + frequencies.put(element, frequencies.getOrDefault(element, 0) - 1); |
| 28 | + } |
| 29 | + } |
| 30 | + |
| 31 | + private void addToFrequency(Map<Integer, Integer> frequencies, int element) { |
| 32 | + frequencies.put(element, frequencies.getOrDefault(element, 0) + 1); |
| 33 | + } |
| 34 | + |
| 35 | + private Map<Integer, Integer> getNumberFrequencies(int[] array) { |
| 36 | + final Map<Integer, Integer> result = new HashMap<>(); |
| 37 | + for (int element : array) { |
| 38 | + result.put(element, result.getOrDefault(element, 0) + 1); |
| 39 | + } |
| 40 | + return result; |
| 41 | + } |
| 42 | +} |
0 commit comments